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#! /usr/bin/env gforth
\ Challenge 199
\
\ Task 2: Good Triplets
\ Submitted by: Mohammad S Anwar
\
\ You are given an array of integers, @array and three integers $x,$y,$z.
\
\ Write a script to find out total Good Triplets in the given array.
\
\ A triplet array[i], array[j], array[k] is good if it satisfies the following
\ conditions:
\
\ a) 0 <= i < j < k <= n (size of given array)
\ b) abs(array[i] - array[j]) <= x
\ c) abs(array[j] - array[k]) <= y
\ d) abs(array[i] - array[k]) <= z
\
\ Example 1
\
\ Input: @array = (3,0,1,1,9,7) and $x = 7, $y = 2, $z = 3
\ Output: 4
\
\ Good Triplets are as below:
\ (3,0,1) where (i=0, j=1, k=2)
\ (3,0,1) where (i=0, j=1, k=3)
\ (3,1,1) where (i=0, j=2, k=3)
\ (0,1,1) where (i=1, j=2, k=3)
\
\ Example 2
\
\ Input: @array = (1,1,2,2,3) and $x = 0, $y = 0, $z = 1
\ Output: 0
CREATE nums 256 CELLS ALLOT
0 VALUE nums_size
0 VALUE x 0 VALUE y 0 VALUE z
: nums[] ( i -- addr )
CELLS nums +
;
: collect_args ( -- )
BEGIN NEXT-ARG DUP WHILE
0 0 2SWAP >NUMBER 2DROP DROP
nums_size nums[] !
nums_size 1+ TO nums_size
REPEAT
2DROP
;
: pop_nums ( -- n )
nums_size 1 < THROW
nums_size 1- DUP nums[] @ ( size-1 n )
SWAP TO nums_size
;
: count_good_triplets ( -- )
0 0 0 { i j k }
0 ( count )
0 TO i
BEGIN i nums_size 2 - < WHILE
i 1+ TO j
BEGIN j nums_size 1- < WHILE
j 1+ TO k
BEGIN k nums_size < WHILE
i nums[] @ j nums[] @ - ABS x <=
j nums[] @ k nums[] @ - ABS y <= AND
i nums[] @ k nums[] @ - ABS z <= AND
IF 1+ THEN
k 1+ TO k
REPEAT
j 1+ TO j
REPEAT
i 1+ TO i
REPEAT
;
collect_args nums_size 6 < THROW
pop_nums TO z
pop_nums TO y
pop_nums TO x
count_good_triplets . CR
BYE
|
